Source : Webster's Revised Unabridged Dictionary (1913)

Incubation \In`cu*ba"tion\, n. [L. incubatio: cf. F.
   incubation.]
   1. A sitting on eggs for the purpose of hatching young; a
      brooding on, or keeping warm, (eggs) to develop the life
      within, by any process. --Ray.

   2. (Med.) The development of a disease from its causes, or
      its period of incubation. (See below.)

   3. A sleeping in a consecrated place for the purpose of
      dreaming oracular dreams. --Tylor.

   {Period of incubation}, or {Stage of incubation} (Med.), the
      period which elapses between exposure to the causes of a
      disease and the attack resulting from it; the time of
      development of the supposed germs or spores.